Manufacture of open-spaced abrasive fabrics



Jan.

C. E. WOODDELL MANUFACTURE OF OPEN SPACED ABRASIVE FABRICS- Filed Sept. 26, 1951 2 Sheets-Sheet l INVENTOR CHARLE$ E. WOODDELL ATTORNEY Jan. 15, 1935- c "5; WQQDDELL 1,988,065

MANUFACTURE OF OPEN SPACED ABRASIVE FABRICS Filed Sept. 26, 1951 2 Sheets-Sheet 2 INVENTOR CHAR LES E. WODDDELL ATTORNEY Patented Jan. 15, 1935 UNE'FED STATES rarest or ies MANUFACTURE or ores-smash ABRASKVE memos Charles E. Wooddell, Niagara Falls, N. EL, assignor to The (Jarborundum (Company, Niagara Falls,

N. Y., a corporation of Pennsylvania Application September 26, 193i, Seriai No. 565,389

Glaims.

' grinding operations performed with fabrics coated with abrasive grains such as those of emery or silicon carbide, the materials to be polished or ground are brought into contact with the abrasive face of the fabric when driven at a high rate of speed. As the fabric is used in this manner, particles of the material being ground break ofi and fill the spaces between the abrasive grains of the fabric, and clog them, resulting in a glazed surface on the fabric which causes the fabric to slide over the surface without the desired and proper grinding and polishing operation being performed. Such glazing of the surface materially shortens the life, and decreases the efficiency, of the abrasive fabric.

Heretofore in the art dealing with the manufacture of abrasive fabrics, in order to prevent the deterioration of the abrasive fabric resulting from the above-mentioned glazing of the surface, it has been recommended that the abra= sive coating should be applied in such a way that portions of backing sheet are left free of the abrasive, thus making clearance spaces within which the ground particles of material may be received and freed from the working portions of the abrasive fabric and thus preventing the glazing action.

Abrasive paper or cloth made in accordance with my invention has been found to have a greater efficiency than any abrasive-coated fabric known heretofore. This greater efliciency is obtained by causing the abrasive-coated portions to bear a particular angular relationship to the direction of travel of the abrasive paper in use. For example, when the abrasive sections and open spaces are in the form of strips, it has been found that the emciency is considerably greater if these strips are at an angle of from 60 to 90 with the direction of travel of the paper.

In the prior art, it has been proposed to provide a hopper, or a series of hoppers, from which the grains fall by gravity in a stream or series of streams transversely of the fabric traveling thereunder and which is to be coated.

The object of this invention is to provide a new and improved method for the manufacture of open-spaced abrasive fabrics whereby a more durable and superior abrasive article is obtained.

In practicing my invention, 1 utilize a mask or shield in combination with the usual apparatus for making abrasive-=coated sheet materials. This mask or shield cooperates with the usual apparatus in such a way that the resulting 5 product has areas in which there is an absence of abrasive grain or an absence of both abrasive grain and adhesive, depending upon the manner in which the mask or shield is applied.

One method of carrying out my invention involves the engagement of the mask or shield i intimate contact with the fabric to be coated. When I cause the mask or shield to be in intimate contact with the fabric I am enabled to produce areas on the finished product that are devoid of adhesive and of abrasive grain by shielding certain areas of the fabric from the adhesive applicator and also from the flow of abrasive grain.

By another method, a shield or mask in proximity to the fabric but not in actual contact with it permits the shielding of the fabric from the flow of abrasive grain but not from the adhesive applicator. The path of the mask or shield in this case may be parallel to or at an angle to that of the fabric.

Several ways of carrying out my invention are illustrated by the appended drawings, in which:

Figure 1 is a diagrammatic view showing the fabric being shielded in part from .the adhesive applicator;

Figure 2 is a diagrammatic view showing the fabric being shielded in part from the adhesive applicator and from the flow of grain;

. Figure 3 is a plan view of one form of mask or shield;

Figure 4 is a diagrammatic view of mask or shield in proximity to the fabric but not in contact therewith; and

Figure 5 shows one form of mask or shield 40 positioned at right-angles to the path of the fabric.

111' the drawings, 2 represents .a roll of fabric 6 to be coated with abrasive grains, with the mask 7 in contact with the fabric as shown in Figs. 1 and 2 or with the mask in proximity to the fabric as shown in Figs. 4 and 5. The mask 7 is made of paper, cloth, metal or any other like or suitable material and has cut-out portions or perforations 12 (Figure 3) therein simulating whatever shape or size of coating it is desired to have upon the finished open-spaced abrasive product. As shown in Fig. 3, these slots or perforations are diagonal, but it is to be understood that they may be round, starshaped, cross-hatched; in the form of letters so that the name of the manufacturer may appear, or in any other form which it may be desirable to have.

, The fabric 6 passes from the roll 2 to the upper surface of theglue roll 4 and between the pressure roll 3 and the glue roll 4 which are driven by any suitable connections in the direcapplication of the glue and thus the glue is applied to the face of the fabric 6 in the form of definite rows, as shown in the drawings, or

- in any other manner, according to the formation of the perforations 12 of the mask 7. Not

only does the pressure roll 3 govern the thickness of the glue coating, but it also acts to hold the -mask securely down against the fabric during the passage of the mask and the fabric be- .tween the pressure roll and the glue roll, so as to prevent the seepage of glue beneath the mask 7 onto the fabric 6.

After the application of the glue to those portions of the fabric 6 which were not blanked but 1 were exposed to the surface of the glue roll 4,

the fabric and mask 7 may be separated while the glue is still wet, or they may be caused to travel together until they have passed beneath the grain feed hopper 9.

The fabric 6 with the mask 7 detached therefrom travels beneath the hopper 9 which contains abrasive grains 8. This hopper has a roller control feed 11 which causes a thin sheet of grains, indicated at 10, .to fall by gravity upon the fabric 6 passing thereunder. However, the grains thus dropped are secured firmly only on those portions which have been coated with glue, the grains dropping upon the spaces between'the glue rows or glue coated spaces (or those spaces covered by th mask 7 during the gluing operation) being caused to fall readily off of the fabric 6 as 'it passes to the drier and to subsequent operations which are ordinarily performed in the manufacture of abrasive paper.

If the mask is not removed from the fabric before the latter passes under the grain feed hopper 9, the abrasive grains fall upon both the fabric and the mask. The fabric and mask then are separated and the coated fabric is passed on to any desired subsequent treatment such as sizing and/or drying, while the mask is treated for the recovery of the abrasive grains on its surface.

The recovery of the abrasive grains from the surface of the mask may be accomplished by treating the mask to remove the adhesive. Washing with water provides an easy way of recovering the abrasive grain from metal masks, and burning of the mask and the adhesive permits ready recovery of grain from a mask made of paper or similar material.

The spattering of abrasive grains onto spaces which are not to be coated has been common in the prior art methods, but my invention pro"- vides a method whereby blanking or masking the fabric during the application of the glue to the fabric is very effective. It will be obvious that should the grains spatter, they would not adhere to those uncoated spaces, but would easily fall off, and only those grains dropping upon the adhesive-coated portions would cling tightly.

The mask may meet the fabric after the fabric 'has been subjected to the gluing operation as shown in Figure 4. The glue-coated fabric and mask pass under the hopper where the abrasive grains are allowed to drop promiscuously upon the exposed portions of the fabric and mask passing therebeneath. Since the mask acts as a blanking medium to the fabric, the fabric receives only those grains which fall upon the portions of ,the fabric exposed by the perforations 12 of the mask 7. Thus, the desired grouping of the abrasive grains upon the paper can be regulated by the perforations in the mask.

Following this application of the grain to both mask and fabric, the mask is detached from the fabric, as shown in Fig. 1, leaving alternatev abrasive-coated and uncoated, rows on the fabric. and is either wound about the roll 13 or, if it is of metal, is taken to a tank (not shown) where it is washed and the abrasive, grains and glue adhering thereto are freed and preserved for future use. If the mask is of paper or similar material it may be burned to recover the grains for use again. 1

The term fabric as usedin the foregoing description of my three applications of the mask is not limited solely to the exact definition of the word, but is intended to cover paper, cloth, or any similar article of thin sheet-like form.

In applying grain to the fabric 6 by means of the mask or shield 7, according to the methods illustrated in Fig. 5, the fabric is coated with an adhesive in the usual'wayby passing it between the glue roll 4 and the pressure roll 3, shown in Figures 1, 2 and 4, where the entire upper surface (as it leaves the roll 3) is coated with glue. Beneath the hopper 9 shown in Figures 1, 2 and 4 containing the abrasive grains the adhesive-coated fabric is passed under a continuous and moving mask 7 which is in the form of a belt, and which passes around rolls l4 and I 15. The mask has perforations or cut out portions 12- therein of any desired form, but as shown in Fig. 5, I prefer to use a continuous straight line of small holes through which small streams of the abrasive grains to be applied are allowed to fall.

It will be readily apparent that as the mask moves simultaneously with the fabric 6, the abrasive grains falling through the perforations in the mask 7 form alternate linesof abrasive coated portions and uncoated portions or open spaces. Whether these lines are diagonal or perpendicular, together with the degree of obliqueness of these lines, depends upon the angle formed between the mask 7 and the fabric 6, and also upon the relative speeds at which the fabric 6 and the mask 7 are traveling.

"For example, as shown in Fig. 5, the fabric 6 is passed beneath the top portion of the con tinuous and moving mask 7, the mask making a circuit about the fabric 6, which with relation to the fabric 6, is at an angle of The speed path of the mask over the fabric will be at a 45 of the fabric and the mask being equal, the angle, and the inclination of the design of the abrasive grains upon the fabric is at a 45 angle. Similarly, if the mask is placed at an angle of 60 to ,the fabric, and the speed of the mask is twice that of the fabric, the lines forming the design will be perpendicular to the sides of the belt.

memes It will thus be seen that by merely varying the speed and angle of the mask, an abrasive coated fabric will be obtained with varying designs.

From the above disclosures, it will be apparent .that the provision. of a mask or shield inlthe application of an abrasive, of an adhesive, or both, to a fabric to form open spaced coated paper is new in the art and has material advantages over prior methods.

It will be understood that various modifications and additions may be made with respect to this invention without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In the process of making abrasive sheets, the steps comprising passing a perforated shield over and across a moving adhesive coated fabric, and passing abrasive granules through the perforations of said shield and onto the said adhesive coated fabric whereby certain areas of said adhesive coated fabric will be coated with abrasive granules.

2. In the process of making abrasive sheets, the steps-comprising passing a moving perforated shield above a moving adhesive. coated fabric and at an angle thereto, adjusting the relative speeds of said shield and said adhesive coated fabric, and passing abrasive granules through the perforations of said shield and onto said adhesive coated fabric, whereby the granular coated and uncoated portions of said fabric will be in a predetermined angular relation with respect to the edge of the fabric.

3. In the process of making abrasive sheets, the steps comprising passing a moving perforated shield above a moving adhesive coated fabric and at an angle of 90 thereto, equalizing the rate of speeds of said adhesive coated fabric and said shield, and passing abrasive granules through the perforations of said shield and onto the adhesive coated fabric, whereby the graular coated and uncoated portions-of said fabric will be at an angle of 45 with respectto the edge of the fabric.

4. In the process of making abrasive sheets, the steps comprising passing a moving perforated shield above a moving adhesive coated fabric and at an angle of 60 thereto, adjusting the rate of speeds of said adhesive coated fabric and said shield'whereby the rate of speed of said shield will be twice that of the adhesive coated fabric, and passing abrasive granules through the perforationsof said shield and onto the adhesive coated-fabric, whereby the granular coated and uncoated portions of said fabric will be perpendicular to the sides of .the fabric.

, CHARLES E. WOODDELL. 

